// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \page 01-qdoc-manual.html
    \previouspage QDoc Manual
    \nextpage Command Index

    \title Introduction to QDoc

    QDoc is a tool used by Qt Developers to generate documentation for
    software projects. It works by extracting \e {QDoc comments} from
    project source files and then formatting these comments as HTML
    pages or DocBook XML documents. QDoc finds QDoc comments in \c
    {.cpp} files and in \c {.qdoc} files. QDoc does not look for QDoc
    comments in \c {.h} files. A QDoc comment always begins with an
    exclamation mark (\b{!})). For example:

    \badcode *
        /\1!
            \class QObject
            \brief The QObject class is the base class of all Qt objects.

            \ingroup objectmodel

            \reentrant

            QObject is the heart of the Qt \l{Object Model}. The
            central feature in this model is a very powerful mechanism
            for seamless object communication called \l{signals and
            slots}. You can connect a signal to a slot with connect()
            and destroy the connection with disconnect(). To avoid
            never ending notification loops you can temporarily block
            signals with blockSignals(). The protected functions
            connectNotify() and disconnectNotify() make it possible to
            track connections.

            QObjects organize themselves in \l {Object Trees &
            Ownership} {object trees}. When you create a QObject with
            another object as parent, the object will automatically
            add itself to the parent's \c children() list. The parent
            takes ownership of the object. It will automatically
            delete its children in its destructor. You can look for an
            object by name and optionally type using findChild() or
            findChildren().

            Every object has an objectName() and its class name can be
            found via the corresponding metaObject() (see
            QMetaObject::className()). You can determine whether the
            object's class inherits another class in the QObject
            inheritance hierarchy by using the \c inherits() function.

        ....
        \1/
    \endcode

    From the QDoc comment above, QDoc generates the HTML \l {QObject}
    {QObject class reference} page.

    This manual explains how to use the QDoc commands in QDoc comments
    to embed good documentation in your source files. It also explains
    how to make a \l {The QDoc Configuration File} {QDoc configuration
    file}, which you will pass to QDoc on the command line.

    \section1 Running QDoc

    The name of the QDoc program is \c {qdoc}. To run QDoc from the
    command line, give it the name of a configuration file:

    \quotation
        \c {$ ../../bin/qdoc ./config.qdocconf}
    \endquotation

    QDoc recognizes the \c {.qdocconf} suffix as a \l{The QDoc
    Configuration File} {QDoc configuration file}. The configuration
    file is where you tell QDoc where to find the project source
    files, header files, and \c {.qdoc} files. It is also where you
    tell QDoc what kind of output to generate (HTML, DocBook XML...),
    and where to put the generated documentation. The configuration
    file also contains other information for QDoc.

    See \l{The QDoc Configuration File} for instructions on how to
    set up a QDoc configuration file.

    \section1 How QDoc Works

    QDoc begins by reading the configuration file you specified on the
    command line. It stores all the variables from the configuration
    file for later use. One of the first variables it uses is \c
    {outputformats}. This variable tells QDoc which output generators
    it will run. The default value is \e {HTML}, so if you don't set
    \c {outputformats} in your configuration file, QDoc will generate
    HTML output. That's usually what you will want anyway, but you can
    also specify \e {DocBook} to get DocBook output instead.

    Next, QDoc uses the values of the
    \l {headerdirs-variable}
    {headerdirs} variable and/or the \l
    {22-qdoc-configuration-generalvariables.html#headers-variable}
    {headers} variable to find and parse all the header files for your
    project. QDoc does \e not scan header files for QDoc comments. It
    parses the header files to build a master tree of all the items
    that should be documented, in other words, the items that QDoc should find
    QDoc comments for.

    After parsing all the header files and building the master tree of
    items to be documented, QDoc uses the value of the \l
    {22-qdoc-configuration-generalvariables.html#sourcedirs-variable}
    {sourcedirs} variable and/or the value of the \l
    {22-qdoc-configuration-generalvariables.html#sources-variable}
    {sources} variable to find and parse all the \c {.cpp} and \c
    {.qdoc} files for your project. These are the files QDoc scans for
    \e {QDoc comments}. Remember that a QDoc comment begins with
    an exclamation mark:  \b {/*!} .

    For each QDoc comment it finds, it searches the master tree for
    the item where the documentation belongs. Then it interprets the
    QDoc commands in the comment and stores the interpreted commands
    and the comment text in the tree node for the item.

    Finally, QDoc traverses the master tree. For each node, if the
    node has stored documentation, QDoc calls the output generator
    specified by the \c {outputformats} variable to format and write
    the documentation in the directory specified in the configuration
    file in the \l
    {22-qdoc-configuration-generalvariables.html#outputdir-variable}
    {outputdir} variable.

    \section1 Command Types

    QDoc interprets three types of commands:

    \list
    \li \l {Topic Commands}
    \li \l {Context Commands}
    \li \l {Markup Commands}
    \endlist

    Topic commands identify the element you are documenting, for example
    a C++ class, function, type, or an extra page of text
    that doesn't map to an underlying C++ element.

    Context commands tell QDoc how the element being documented
    relates to other documented elements, for example, next and previous page
    links, inclusion in page groups, or library modules. Context
    commands can also provide information about the documented element
    that QDoc can't get from the source files, for example, whether the
    element is thread-safe, whether it is an overloaded or reimplemented function,
    or whether it has been deprecated.

    Markup commands tell QDoc how text and image elements in the
    document should be rendered, or about the document's outline
    structure.
*/

